| 摘要 |
PURPOSE:To improve the detecting speed, by impressing a voltage to a photoelectric conversion element in advance before the detection of a signal current, for excluding the restriction due to a time constant of a resistor and a wiring capacitance of the photoelectric conversion element. CONSTITUTION:A photoelectric conversion element group 21 is divided into four blocks and each is connected to a power supply 23 via a common switch group 22. Further, the block of the element group 21 is divided into two and each is connected to individual switch groups 26, 27. Then, common switches 22a-22d are turned on and off at waveforms 22a-22d, individual switches 26a-26d are turned on and off at waveforms 26a-26d, and individual switches 27a-27d are turned on and off at waveforms 27a-27d respectively. Through the on/off control in this way, a voltage is impressed to the photoelectric conversion element before the detection. Thus, the detecting speed is improved by excluding the restriction due to the time constant consisting of the resistance and the wiring capacitance of the photoelectric conversion element. |
